﻿using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace skydream
{
    /// <summary> 
    /// DES加密字符串 
    /// </summary> 
    /// <param name="DesHelp">des加密</param> 
    public class DesHelp
    {
        //默认密钥向量 
        private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
        /**/
        /**/
        /**/
        /// <summary> 
        /// DES加密字符串 
        /// </summary> 
        /// <param name="encryptString">待加密的字符串</param> 
        /// <param name="encryptKey">加密密钥,要求为8位</param> 
        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns> 
        public static string DESEncrypt(string encryptString, string encryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                //CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, 0, inputByteArray.Length);

                int i = inputByteArray.Length;
                cStream.FlushFinalBlock();
                string temp = null;
                temp = Convert.ToBase64String(mStream.ToArray());

                //byte[] bytes=new byte[mStream.ToArray().Length];
                //bytes=mStream.ToArray();
                //for (int s = 0; s < bytes.Length; s++)
                //{
                //    temp = bytes[s].ToString();
                //}
                //temp = Convert.ToBase64String(mStream.ToArray());
                //bytes = Convert.FromBase64String(temp);
                //string temp2 = "";
                //temp2 = Encoding.Default.GetString(bytes);//bytes[i];

                //return temp2;
                return temp;
            }
            catch
            {
                return encryptString;
            }
        }

        /**/
        /**/
        /**/
        /// <summary> 
        /// DES解密字符串 
        /// </summary> 
        /// <param name="decryptString">待解密的字符串</param> 
        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param> 
        /// <returns>解密成功返回解密后的字符串，失败返源串</returns> 
        public static string DESDecrypt(string decryptString, string decryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }

    }
}
